Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Regular Expression E Metacharacter in Java.
The subexpression/metacharacter “\E” ends the quoting begun with \Q. i.e. you can escape metacharacters in the regular expressions by placing them in between \Q and \E. For example, the expression [aeiou] matches the strings with vowel letters in it.
Example
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class SampleProgram {
public static void main( String args[] ) {
String regex = "[aeiou]";
Scanner sc = new Scanner(System.in);
System.out.println("Enter input string: ");
String input = sc.nextLine();
//Creating a Pattern object
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(input);
if(matcher.find()) {
System.out.println("Match occurred");
}else {
System.out.println("Match not occurred");
}
}
}Output
Enter input string: sample Match occurred
But, if you use the same expression with in \Q and \E as \Q[aeiou]\E It matches the same sequence of characters “[aeiou]” in the given string. In short the meta characters loses their meaning and will be treated as normal characters.
Example
import java.util.Scanner;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class SampleProgram {
public static void main( String args[] ) {
String regex = "\Q[aeiou]\E";
Scanner sc = new Scanner(System.in);
System.out.println("Enter input string: ");
String input = sc.nextLine();
//Creating a Pattern object
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(input);
if(matcher.find()) {
System.out.println("Match occurred");
} else {
System.out.println("Match not occurred");
}
}
}Output 1
Enter input string: sample Match not occurred
Output2
Enter input string: The letters [aeiou] are vowels in English alphabet Match occurred
Updated on: 10-Jan-2020
405 Views
Advertisements